Scalable and robust silica aerogel materials from ambient pressure drying

Abstract

Aerogels constitute one of the most effective superinsulation materials, typically featuring remarkably low values of thermal conductivity due to their extremely high porosity comprised mostly of mesopores with an average...

Manufacturing silica aerogel and cryogel through ambient pressure and freeze drying

“…This technique primarily introduces some degree of elasticity to the resulting composites, while it also offers the possibility of improving the thermal performance of fiber-based products as a direct result of the aerogel precursor being used during the production of the composite material. 25 In this work, both cellulose nanofiber and glass (acid resistant borosilicate) microfiber (referred as ceramic-fiber for simplicity) will be used. Through the incorporation of optimal quantities of aerogel precursor, an advanced cross-linking scheme between fiber and aerogel can be achieved as illustrated in the SEM images included in Fig.…”

“…Hence, it is indispensable to achieve scalable manufacturing of insulation materials by mitigating the surface exchange and surface modication of the wet-gel precursor. 25 Here, we report that the silica cryogels obtained from the FD process show a thermal conductivity as low as 23 mW m À1 K À1 , with a specic surface area of 369.4 m 2 g À1 , and a porosity of 96.7%. Ambient-pressure-dried aerogels (referred as silica aerogels), on the other hand, have a thermal conductivity of 23.6 mW m À1 K À1 , a specic surface area of 473.8 m 2 g À1 , and a porosity of 97.4% respectively.…”

“…It is worth mentioning that 600 C has been selected as the optimal sintering temperature following results from thermal conductivity tests of aerogel specimens (sintered to 300 C, 400 C, 500 C, and 600 C respectively) performed in previous work. 25 Moreover, BET/BJH tests also conrm that better results are obtained for samples that have been sintered to 600 C, as shown in Table S1 and Fig. S11 † respectively.…”

“…Hence, it is indispensable to achieve scalable manufacturing of insulation materials by mitigating the surface exchange and surface modification of the wet-gel precursor. 25 …”

Hierarchical Cellulose Superinsulation Membrane

“…This sintering temperature was selected following a thorough analysis of the results from thermal conductivity tests on aerogel specimens (sintered to 300, 400, 500, and 600 °C) produced in previous research work. [ 34 ] Ball milling of the aerogel was then performed by means of a vertical, high‐energy planetary ball mill featuring dual rotating direction, in order to further grind it into an extremely fine powder through this grinding mechanical technique. The aerogel was placed in a sealed container with ceramic balls, and a rotating speed of 300 rev min −1 was applied during 60 min (30 min in each rotating direction), after which the finely ground aerogel powder was ready for further use.…”